He took off his coat, _____ all his pockets, but couldn’t find his key.

A．searched

B．searching

C．to search

D．searches

胆固醇是下列化合物前物，但除外（）

A.胆汁酸

B.维生素D₃

C.雄激素

D.雌激素

E.绒毛膜促进腺激素